Object stacker

ABSTRACT

An automatic machine for stacking objects, as metal ingots, having a loading unit with a movable carriage operable to carry ingots to an ingot collector and holding unit. The ingots are collected on movable supports located above a rotatable elevator platform. On movement of the supports to the open positions, the ingots are transferred to the elevator platform or the top layer of ingots carried by the elevator platform. Consecutive layers of ingots are normally disposed with respect to each other by rotating the elevator platform after each layer of ingots is transferred to the top layer of ingots. The complete stack of ingots is pushed with a hydraulic ram from the elevator platform onto a roller stack conveyor.

3 United States Patent [72'] Inventor" WallaceM; Thompson Cordele, Ga. f ,121} AppLNo. 761,103 [22] Filed Sept. 20, 1968 [45]"Pat ented Jan-12,1971 [73], Assignee American l-loist8zDerrick Company St. Paul, Minn. I

a corporation of Delaware [54] OBJECTSTACKER 16 Claims, :12 Drawing Figs.

"[52] U.S.Cl..., 214/6,

' j t 198/219 [51] lnt.Cl..... B65g57/18 [50] Field ofSearch 214/6K, i 65,611, 6?, 6A; 198/21 9,218

. [56] ReferencesCited UNITED STATES PATENTS 2,985,322 5/1961 Parker"; 2l4/6(P) 2,607,501 8/1952 Jeffrey 214/6(K) 2,697,388 12/1954 -l-lansen etal,... 214/6.5UX 2,984,838 5/1961 Parker 2l4/6(H)X '2l4/6(H) Von Gal, Jr.

Primary Examiner-Gerald M. Forlenza Assistant Examiner-Robert J. Spar Alt0rneyBurd, Braddock & Bartz ABSTRACT: An automatic machine for stacking objects, as

' metal ingots, having a loading unit with a movable carriage operable to carry ingots to an ingot collector and holding unit.

a The ingots are collected on movable supports located above a rotatable elevator platform. On movement of the supports to the open positions, the ingots are transferred to the elevator platform or the top layer ofingots carried by the elevator platform. Consecutive layers of ingots arenorrnally disposed with r respect to each other by rotating the elevator platform after each layer of ingots is transferred to the top layer of ingots. The complete stack of ingots is pushed with a hydraulic ram from the elevator platform onto a roller stack conveyor.

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. 1 oBJEcT srAcKeR SUMMARY or INVENTION The invention broadly relates to a machine operable to collect a plurality of. objects into a layer of objects and then successively pla'cethe layers of objects into a stack. The machine has a loading unitoperable to receive objects and move the objects to anobjectcollecting unit. The collecting unit posi- When the stack is completed a means removes the entire stack from the elevator means.

IN THE DRAWINGS I FIG. 1 is a plan view of the object stacker of the invention; F IG. 2 is a side elevational view of the object stacker of FIG.

FIG. 3 is an enlarged sectional view taken along the line 3-3 FIG. 4. is an enlarged sectional view taken along the line 4-4 FIG. 5 is an enlarged sectional view taken along the line 5-5 of FIG. 4;

FIG. 6 is an enlarged sectional view taken along the line 6-6 Movable ingot guide arms 31 are pivotally connected to support 32 mounted on the lower portion of frame 27. An

upright hydraulic ram 33 connected to the guide arms 31 and the frame 27 is operable to hold the guide arms in a position shown in full lines in FIG. 4 toallowthe ingots to moveonto the loading unit. On actuation of the hydraulic ram 33 the guide arms 31 pivot to reject or the dotted line position where the forward end of the guide arms 31 cooperate with a curved ingot director 34 to deflect ingots onto atransverse inclined reject chute 36 in the direction of arrow 35A. The ingot director 34 guides ingots received from the ingot casting machine conveyor drum 35 onto the loading unit 16.

As shown in FIGS. 3 and 4, locatedbetween the side members of the frame 27 is'a movable carriage indicated generally at 37 operable to receive the ingots and elevate the ingots to the collector and holding unit 17. The carriage has a pair of directed flanges 41 and 42 of the frame 27. A first platform 43 FIG. 9 is a schematic diagram of the fluid control system of the object stacker; I v FIG. 10 is a schematic diagram of the hydraulic rams andlimit switch controlsj'and.

FIGS. 11A and llB'together gramof the electrical control system of the object stacker.

Referring to the drawings there isshown in FIG. 1 the object Stacker 15 is operable to sequentially receive ingots discharged from an ingot forming or casting machine. Each ingot is carried by alcadirig unit 16 to a collector and holding unit 17 operative to locate a plurality of ingots in side-by-side' -rclative relation in a layerfor stackingLLQcated below the holding unit 17 is a stacking elevator '18- operable to'support and stackthe layer of ingots-delivered by 'the holding unit in alternately directed layers. When a stack of ingots hasbeen collected on the elevator. the entire stack is ejected from the constitute the electrical diaw elevator to a stack conveyorl9 operative to carry the stack of I ingots to a discharge: location. Thestacker 15 is automatic in operation and has manually operated reject controls to rem'ovedefective ingots before they are collected into a layer inclined frame 27 movably supported on the cross members.

24 and 25. A hinge connection28 pivotally mounts the lower portion of the frame 27 to the cross member 25. The upper end is supported on the cross member 24 by a spacer member 29. Member 29 may be a plurality of coil springs located in the upright sleeves. The tops of the springs can engage a transverse member of frame 27 and-thereby relieve the collector.

and holding unit 17 and stacking elevator 18 of eccentric loads.

' nected to a cross member 49 secured to the side members 38 and 39. The upper platform 45 has downwardly projected legs .50 connected to a hydraulic ram 51. The lower end of the hydraulic ram 51 is connected to the legs 47. The rear sides of the platforms 43 and 45 have upright ribs 43A and 45A acting as stops preventing rearward movement of ingots resting on the platforms.

Located adjacent opposite sides of the upper platform 45 are upright pivotally mounted first retainer arms 52 and 53 which receive and support ingots from the lower platform 43 at an'inspection station. As shown in FIG. 3, retainer arms 52 and 53 are connected to frame 27 by hinge pivot connections 52A and 53A. Springs 52B and 538 operating on rods 52C and 53C bias the retainer arms 52and 53 toward each other in alignment with the ends of the ingot 61A resting on top of the retainer arms 52 and 53 in the inspection position.

I As shown in FIG. 5, located at the upper end of the loading unit 16 are a pair of second pivotally mounted retainer arms 54 and'55 which receive the ingot 61A from the upper platform 45 and hold the ingot in a position where it can be picked up by the collector and holding unit 17. Springs 54A and 55A cooperating with rods 54B and 55B bias the arms 54 and 55 toward each other adjacent the ends of ingot 61B. Located below the upper end of the loading unit 16 is a laterally directed reject conveyor 56 which receives the defective ingots that are dumped from the upper platform 45.

The carriage 37 is moved from the lower loading position.

i as shown in FIG. 4, to an upper unloading position and back to the loading position on the operation of a hydraulic ram 57. One end of the ram 57 is secured to the midportion of a cross member 58 connecting the bottom ends of the frame 27. The piston rod 59 of the ram 5 7'is connected to the carriage bottom cross member 49.

Returning to FIGS. 1 and 2, collector and holding unit 17 has a pair of facing inwardly directed flanges 60 secured to frame 22 adjacent the forward top edges of arms 54 and 55 providing side supports for ingots moved from the arms. A pair of movable plates 62 and 63 supported by the frame 22 in horizontal alignment with the flanges 59 and 61 serve as holding members for the ingots. Plate 62 is moved by a pair of hydraulic rams 64 and 66 connected to opposite sides of the plate and to a U-shaped frame 67 secured to the side of frame 22. Plate 63 is moved by a pair of hydraulic rams 68 and 69 connected to opposite sides of the plate and to a U-shaped frame 71. The inside edges of the plates 62 and 63 project inwardly from frame 22 providing side supports for the ingots in the collector and holding unit 17.

As shown in FIG. 6, plate 62 is slidably located in a horizontal slot 72 in member 73'secured to the bottom of flange 22.

Hydraulic rams 64 and 66 operate to reciprocate the plate 62 in slot 72 to release the ingots. Plate 63 is slidably located in a similar slot in a member (not shown) secured to the opposite side of frame 22.

The ingot 61B is moved from the loading unit 16 over the flanges 60 onto the plates 62 and 63 by a movable transverse puller 74. Pivotally mounted on the puller 74 is a pair of downwardly projected fingers 76 which engage the back side of the ingot 618 on movement of the puller in the forward direction by a hydraulic ram 77. The outer end of the piston rod 78 is secured to the midportion of the puller 74. Ram 77 is mounted on a cross member 79 secured to frame 22.

On operation of the loading unit 16, ingot 61 is guided by the director 34 and positioned on the lower platform 43 by the concave curved edges of the guide arms 31 and the support 32 as shown in FIG. 4. On extension of the hydraulic ram 57-the carriage 37 moves to the up position whereby the lower ingot 61 is carried to the top of the first pair of retainer arms 52 and 53 as shown by second ingot 61A. The ingot resting on the first retainer arms 51 and 52 has been carried to the top of the second retainer arms 54 and 55 as shown by third ingot 61B. Ingot 61B is in the position to be picked up by the collector and holding unit 17. If on visual inspection of the ingot 61A it is defective the inspector manually actuates the controls for the reject hydraulic ram 51 raising the platform 45 to dump the ingot 61A onto the reject conveyor 56.

The puller 74 is sequentially moved by the hydraulic ram 77 until five ingots are collected on the plates 62 and 63. The group or layer of five ingots are then transferred to the stack of ingots on a table 81 of the elevator 18. The table 81 has a plurality of elongated rollers 81A which provide for the rolling movement of the stack of ingots onto the stack conveyor 19. As shown in FIG. 4, the table 81 supports separate normally positioned successive layers of ingots. The table 81 is sequentially turned approximately 90 so that the successive layers of ingots are in normally disposed positions.

The table 81 is raised and lowered through the use of an upright hydraulic ram 82 mounted on the stacker frame with an upright collar 83. The lower end of ram 91 extends into a hole 84 in the floor 21. The normal position of the elevator table 84 for the top layer of ingots is about one-eighth inch under the plates 62 and 63. On the retraction of the plates 62 and 63, the layer of ingots held by the plates are deposited on the table or previous layer of ingots. The hydraulic ram 82 lowers the table approximately four inches and the plates 62 and 63 move inwardly. When the required number of layers of ingots are placed on the elevator 18, the hydraulic ram 82 is fully lowered and the stack is pushed onto the stack conveyor 19. After the stack of ingots leaves the elevator 18 the hydraulic ram 82 returns the platform 81' to the position adjacent the bottom of the plates 62 and 63.

As shown in FIG. 8, the hydraulic ram 82 has an upright piston rod 86 secured to a cross head 87 Upright guide rods 88and 89 are secured to opposite ends of the cross head 87. The guide rods 88 and 89 project downwardly through sleeve bearings 91 and 92 secured to the frame 20 to stabilize the cross head 87. The bottom center portion of platform 81 has downwardly directed boss 93 with a bore 94 to receive the upper end of piston rod 86. The table 81 is rotated in opposite angular directions approximately 90 relative to the head 87 by a hydraulic ram 96 having a piston rod 97. The forward end of the piston rod 97 is connected to a leg 98 secured to the bottom of table 81 by a pivot connection 99, The opposite end of the hydraulic ram 96 is attached to an arm 101 secured to the head 94 by a pivot pin 102.

The stack of ingots on the table 81 is pushed from the table onto the stack conveyor 19 by a pair of hydraulic rams 103 having a flat upright foot 104. Rams 103 are mounted on a transverse beam 106 extended between and secured to the upright posts 23.

The stack conveyor 19, shown in FIG. 1, has a pair of spaced parallel side angle members 107 and 108 which slope at a slight angle downwardly from the elevator 18. A plurality of transverse side-by-side rollers 109 are rotatably mounted on the side members 107 and 108 to form a movable floor for the stacks of ingots moved from the elevator 18.

Referring to FIG. 9, there is shown the fluid control system indicated generally at 111 for the hydraulic rams which automatically control the operation of the stacker 15. The control system is a hydraulic fluid pressure system'having a motor 112 driving a pump 113. The pump l13draws hydraulic fluid from a reservoir 1 14 through a filter 116 and discharges the hydraulic fluid into a line 1 17. Interposed in line 117 is a pressure relief valve 118 and a pressure gauge 119. The line 117 is connected toa line 121 leading to the elevator ram 82. A flow control valve 122'in line 121 is connected to a four way valve 123 operable to alternately exhaust, supply and lock fluid in the opposite ends of the hydraulic ram 82. Solenoids 124 and 126 are operative to control the valve 123. Connected in the line leading from the head or lower end of the elevator ram 82 is a counterbalance valve 127 which automatically compensates for the weight of the load on the elevator 18.

Ejector rams 103 are connected to four way valve 128 controlled by solenoid 129. A flow control valve 131 is interposed in the line connecting valve 128 to line 121. Both valves 123 and 128 are connected to a common reservoir return line 132.

A pressure reducing valve 133 interposed in line 121 separates the elevator and ejector hydraulic system from the remainder of the rams. Valve 133 substantially reduces the pressure to operate the remainder of the system. For example, pressure relief valve 118 is set at 600 psi. and pressure relief valve 133 is set at 200 p.s.i. A pressure gauge 134 is connected to the lie line 121 adjacent the pressure relief valve 133.

The two pairs of collector rams 64, 66 and 68, 69 are controlled with a flow control valve 136 and a four way valve 137 operated with a solenoid 138. The pusher ram 77 is operated in a similar manner through the use of a flow control valve 139 and a four way valve 141 operated with a solenoid 142.

The loading hydraulic ram 57 is controlled with a four way valve 143 operated with solenoid 144 and connected to a flow control valve 146. lngot guide and reject rams 33 are controlled by a four way valve 147 operated with solenoid 148. A flow control valve 149 is interposed in the line connecting valve 147 to line 121. A four way valve 151 operated with a solenoid 152 and flow control valve 153 connects the line 121 to the reject ram 48. A four way valve 154 operated with a solenoid 156 and flow control valve 157 connects the line 121 with the reject ram 51.

A separate four way valve 158 operated by solenoids 159 and 161 and a flow control valve 162 connects line 121 with the elevator rotating hydraulic ram 96. The flow regulators are operative to reduce the speed of operation of the rams. All of the four way valves are connected to the return line 132.

Referring to FIGS. 11A and 1113 there is shown an electrical diagram with limit switches LS'l LS-22 correlated with the solenoids operating valves for hydraulic cylinders of the object stacking machine, This diagram is described in conjunction with the electrical control system shown in FIG. 10. The control system is operable to sequentially and automatically operate the fluid control system indicated generally at 111. Three power lines 163 connected to a master control switch 164 provide 3-phase power to electric motor 112. A transformer 166 is used to supply power to a pair of lines 167 and 168. Manually operated switches 169 and 171 connected in lines leading to the solenoids 148 and 156 respectively control the operation of the ingot guide reject solenoid 148 and the conveyor upper reject solenoid 156. These switches are operated by the person inspecting the ingots on the loading unit to manually reject defective ingots.

The electrical control system 111 has a master switch 172 for changing the operation of the system from automatic to a manual. Switch 172 is operable to selectively connect the line 168 with a line 173 or an automatic starting circuit.

The manual operation of the stacker is provided primarily for set up and maintenance purposes. Manually operated switches are connected to the line 173 and the solenoids 'ble to raise the elevator 18.

manual operation, the master switch 172 ismoved to the.

closed positionconnectingthe line 173 with the line 168. The various parts of the stacker may bein'd'ependently operated by selectively actuating the manually operated switches. Switch 174 controls the conveyor ram 48 of the loading unit. A second switch 176 operates to open the circuit to solenoid 152 and close the circuit to the collector ram 77 with the use of the switch 176A. The second conveyorram 51 is operated with the use of a switch 177 whichis'also connectedto a switch 177A in the line to the collector ram 77.

The release of plates 63 and 64 is manually controlled with o the switch 178 co nnected to the solenoid 138. Switches 179 and 181 operate to lower the elevator 18 by controlling the solenoid 124. The elevator platform 81 is selectively rotated in l the counterclockwise andclockwise directions with the use of pairs of related switches 182 and 183. The eject cylinder 103 I -is controlled bymanual switch 184 operating solenoid 129, A

pair of switches l86and 187 control the solenoid 126 opera- In the automatic mode of operatiomthe switch 172 is in the raise full line position. When the ingot is delivered to the first platform 43 the limit switch LS-l. is closed indicating the presence of an ingot. With the rams' 48'and 51 fully retracted the limit switch LS-2 is closed thereby initially starting the upward movement of the conveyor rams. Limit switch LS-3 is closed nearthe end of the strokesof the rains 48 and 57. Limit switch LS-4 controls limit switchLS-7 to coordinate the conveyor ram57 with the collector-ram 77. When the conveyor ram 57 is fully extended, limit switch LS-5 is closed.When the collector ram 77 is .fully closed the limit switch LS-6 is opened allowing the ram 77 to extend to pick another ingot.

When five ingots are collected on the holding plates 62 and 3 63, the limit switch LS 8 "is closedthereby raising the elevator l8 up'adjacent the bottom of the plate 62 and 63. The ingots on the plates 62 and, 63 are released by closing the limit switch LS-8 which energizes solenoid 138 releasing the ingots to the top of the elevator o'rthe top laycr qfjt' gots on the elevator.

The elevator 82 is then lowered on operation of limit switches LS-9, LSrIO, LS-1l2aridLS 12 which operate in conjunction with openin'gland closing of the plates62 and 63L The elevator platform is rotated, selectively in a clockwise and counterclockwise direction with, on operation of limit switches LS-1 3,

LS-l4 and'LS-IS whichcontrol the solehoids 159 and 161.

o 1. An apparatus for automatically stacking a plurality of ob jects comprising: a loading means for receiving objects one at a time at a receiving location and including a movable carriage for moving the objects from the receiving location to a pick up location, said loading means having means for holding an object at an inspection station located before the pick up location, means for removing a rejected object from the loading means said movable carriage then moving an accepted object from the inspection station to the pick up location, said movable carriage having a first member for receiving an object and moving it to the inspection station and a second member for moving the object from the inspection station to the pick up location, means for the moving the carriage, holding means for receiving objects from the pick up location and collecting a plurality of objects in side'by-side relation relative to each other at a holding location spaced from the pick up location, means to move the objects from the pick up location to the holding location, said receiving location; pick up location, inspection station and holding location located in general longitudinal alignment with each other, elevator means for receiving and stacking the plurality of objects from the holding means, said elevator means located directly below the holding location of the holding means whereby the collected objects move downwardly onto the elevator means, and means for moving the plurality of stacked objects from the elevator means to a discharge location.

2. The apparatus of claim 1 including a frame, pivot means mounting one end of the loading means on the frame and means supporting the other end of the loading means.

3. An apparatus for stacking objects comprising: loading means for receiving objects and moving objects to a pick up location, holding means for receiving objects from the pick up location and collecting a plurality of objects, elevator means .for receiving and stacking the plurality of objects from the holding means, and means for moving the plurality of objects from the elevator means to a discharge location, said loading means having side members for holding an object at an inspec- 40 tion station, a carriage movable between the side members. a first platform mounted on the carriage for receiving an object and carrying the object to the side membersand a second platform pivotally mounted on the carriage for moving the object from the side members to the pick up location.

4. The apparatus of claim 3 including means to pivot the second platformto dump the object from the loading means.

When the stacljof ingots on the elevator platform is completed the limit switch LS-l6 is closed operatingthe eject.

ram 103 which'pushes the ingots onto the elevator 19. After the stack of ingots has been removed from the elevator platform, limit switch LS-2 2 closes whereby the elevator platform is raised to receive the second stack of ingots. Limit switches LS-19,.LS -20 and LS-ZI-Control the ultimate upper limit of the movement of theelevator and are actuated by the collection of five ingots onthe plates 62 and 63.

The'stacking sequenceof the stacker isas follows:

ingots are delivered fromthe jcasting ma'chine down the 5 The apparatus of claim 3 wherein the holding means includes first movable means for collecting a plurality of objects,

and second movable means for-supporting the plurality of oh delivery chute to the first platform 43. Ram 57 carries the ingot to the inspection stop on the second platform 45. A

' nonstandard ingot is rejected by actuating the manually operated switch 171 which dumps the ingot on the reject conveyor 56. The standard ingot is moved from the inspection stop to the top of the loading unit 16 by the cylinder 51. The ram 77' on retracting movesthe ingot onto the collector holding plates 62v and 63. This procedure is repeated until five ingots are collected sideby-side on the holding plates 62 and 63. These plates are retracted to deposit ingots on the elevator platform 81. After the ingots are on the elevator platform, the elevator lowers and rotates approximately 90 to receive the next layer of ingots. When ten layers arestacked on the elevator platform, the elevator is loweredand the stack of int gots is ejected onto the out conveyor onto the second movable means.

7. The apparatus of claim 5 wherein the second movable A means includes a pair of plates supporting opposite ends of the objects and rams for moving each plate away from the ends of the objects.

8. The apparatus of claim 3 wherein the elevator means includes a movable platform located below the holding means for supporting the plurality of objects.

9. The apparatus of claim 8 wherein the elevator means includes means for rotating the platform about an upright axis.

10. The apparatus of claim 8 including an upright hydraulic ram and means mountingthe platform on the ram.

11. The apparatus of claim 3 including a conveyor means adjacent the elevator means for receiving the stack of objects from the elevator means.

. 12. The apparatus of claim 11 wherein the means for moving the objects from the elevator means comprise a hydraulic ram operable to push the stack of objects from the conveyor means.

15. The apparatus of claim 14 wherein: the means to move the plates comprise fluid motor means connected to each plate.

16, The apparatus of claim 1 whereinzthe holding means includes a pair of movableplates supporting opposite ends of the plurality of objects, and means to move the plates away from each other, whereby the objects fall onto the elevator means or on top of objects carried by the elevator means.

@2 3 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,554,388 Dated January 12, 1971 Inventor) Wallace M. Thompson It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 2 line 23 "40" should be 46 Column 4 line 56 should be Column 5 line 19 should be Signed and sealed this 11 tn day of May 1 971 (SEAL) Attest:

EDWARD M.FIETGHER,JR. WILLIAM E. SCHUYLER, JR. Attesting Officer Commissioner of Patents 

1. An apparatus for automatically stacking a plurality of objects comprising: a loading means for receiving objects one at a time at a receiving location and including a movable carriage for moving the objects from the receiving location to a pick up location, said loading means having means for holding an object at an inspection station located before the pick up location, means for removing a rejected object from the loading means said movable carriage then moving an accepted object from the inspection station to the pick up location, said movable carriage having a first member for receiving an object and moving it to the inspection station and a second member for moving the object from the inspection station to the pick up location, means for the moving the carriage, holding means for receiving objects from the pick up location and collecting a plurality of objects in side-by-side relation relative to each other at a holding location spaced from the pick up location, means to move the objects from the pick up location to the holding location, said receiving location, pick up location, inspection station and holding location located in general longitudinal alignment with each other, elevator means for receiving and stacking the plurality of objects from the holding means, said elevator means located directly below the holding location of the holding means whereby the collected objects mOve downwardly onto the elevator means, and means for moving the plurality of stacked objects from the elevator means to a discharge location.
 2. The apparatus of claim 1 including a frame, pivot means mounting one end of the loading means on the frame and means supporting the other end of the loading means.
 3. An apparatus for stacking objects comprising: loading means for receiving objects and moving objects to a pick up location, holding means for receiving objects from the pick up location and collecting a plurality of objects, elevator means for receiving and stacking the plurality of objects from the holding means, and means for moving the plurality of objects from the elevator means to a discharge location, said loading means having side members for holding an object at an inspection station, a carriage movable between the side members, a first platform mounted on the carriage for receiving an object and carrying the object to the side members and a second platform pivotally mounted on the carriage for moving the object from the side members to the pick up location.
 4. The apparatus of claim 3 including means to pivot the second platform to dump the object from the loading means.
 5. The apparatus of claim 3 wherein the holding means includes first movable means for collecting a plurality of objects, and second movable means for supporting the plurality of objects, means for moving the second movable means to a position whereby the plurality of objects are transferred to the elevator means. 6 . The apparatus of claim 5 wherein the first movable means includes a hydraulic ram and a puller member connected to the ram movable by the ram to move the objects onto the second movable means.
 7. The apparatus of claim 5 wherein the second movable means includes a pair of plates supporting opposite ends of the objects and rams for moving each plate away from the ends of the objects.
 8. The apparatus of claim 3 wherein the elevator means includes a movable platform located below the holding means for supporting the plurality of objects.
 9. The apparatus of claim 8 wherein the elevator means includes means for rotating the platform about an upright axis.
 10. The apparatus of claim 8 including an upright hydraulic ram and means mounting the platform on the ram.
 11. The apparatus of claim 3 including a conveyor means adjacent the elevator means for receiving the stack of objects from the elevator means.
 12. The apparatus of claim 11 wherein the means for moving the objects from the elevator means comprise a hydraulic ram operable to push the stack of objects from the conveyor means.
 13. The apparatus of claim 3 including: a frame, pivot means mounting one end of the loading means on the frame, and means supporting the opposite end of the loading means adjacent the pick up location.
 14. The apparatus of claim 3 wherein: holding means comprise a pair of movable plates supporting opposite ends of the objects, and means to move the plates away from each other whereby the objects are free to fall onto the elevator means or on top of objects carried by the elevator means.
 15. The apparatus of claim 14 wherein: the means to move the plates comprise fluid motor means connected to each plate. 16, The apparatus of claim 1 wherein: the holding means includes a pair of movable plates supporting opposite ends of the plurality of objects, and means to move the plates away from each other, whereby the objects fall onto the elevator means or on top of objects carried by the elevator means. 